Zero defocus reference for obj lens seems to be off - Githubissues

Ivanlh20 / multem

MULTEM is a powerful and advanced collection of C++ routines with CUDA support, designed to perform efficient and accurate multislice simulations for various TEM experiments such as HRTEM, STEM, ISTEM, ED, PED, CBED, ADF-TEM, ABF-HC, EFTEM, and EELS.

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Zero defocus reference for obj lens seems to be off #51

Closed FVegaIbanez closed 1 year ago

FVegaIbanez commented 1 year ago

I get different results when running an EWRS reconstruction by setting the obj_lens_zero_defocus_type manually:

Case 1: Parameters: SPECIMEN ==> SrTiO3 crystal:

im.na = 20, im.nb = 20, im.nc = 200 PARAMETERS:
im.nx, im.ny = 1024
im.thick_type = 2 (through-thick), im.thick = c:c:1000
aberrations = 0 (all), im.cond_lens_outer_aper_ang = 21.0
im.iw_type = 2
im.iw_x = im.spec_lx/2, im.iw_y = im.spec_ly/2;
im.pn_nconf = 40;
im.obj_lens_zero_defocus_type = 2 (middle)

From the previous parameters, I obtain the following cross-section along the optical axis:

If I now keep the exact same parameters, changing only:

im.obj_lens_zero_defocus_type = 4 (user define)
im.obj_lens_zero_defocus_plane = im.spec_lz/2

The image I obtain now is:

FVegaIbanez commented 1 year ago

I would like to know if these 2 values (middle and user-defined defocus reference are supposed to be the same or not)